Nursing Elites

1. Fill in the blanks in the following sentence: Enzymes are ________ molecules that serve as _______ for certain biological reactions.

• A. complex; suppressors
• B. acidic; triggers
• C. small; targets
• D. large; catalysts

Correct answer: D

Rationale: Enzymes are large molecules that act as catalysts, accelerating chemical reactions by lowering the activation energy required for the reactions to occur. In the context of biological reactions, enzymes function as catalysts, not suppressors, triggers, or targets. The use of 'large' and 'catalysts' accurately describes the nature and role of enzymes in facilitating biological processes.

2. Which of the following enzymes is responsible for adding a nucleotide to a growing DNA chain?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.

3. What is the primary function of the respiratory system?

• A. to create sound and speech
• B. to take oxygen into the body while removing carbon dioxide
• C. to transport nutrients to the cells and tissue of the body
• D. to act as a barrier between the body’s organs and outside influences

Correct answer: B

Rationale: The primary function of the respiratory system is to take oxygen into the body through inhalation and remove carbon dioxide through exhalation. Oxygen is essential for cellular respiration and energy production, while carbon dioxide is a waste product that needs to be expelled from the body. This process is vital for the functioning of the body's cells and tissues. Choices A, C, and D are incorrect because sound and speech production, nutrient transport, and acting as a barrier against outside influences are not the primary functions of the respiratory system. While the respiratory system is involved in speech production to some extent, its primary role is in gas exchange for respiration.

4. What is the term for the small air sacs in the lungs where gas exchange (oxygen and carbon dioxide) takes place?

• A. Bronchi
• B. Alveoli
• C. Trachea
• D. Bronchioles

Correct answer: B

Rationale: The correct answer is B: Alveoli. The alveoli are the small air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the bloodstream through the alveoli, while carbon dioxide from the bloodstream passes out of the body through the alveoli. Choice A, Bronchi, are the main airways in the lungs and not the site of gas exchange. Choice C, Trachea, refers to the windpipe, which is a different structure than the alveoli. Choice D, Bronchioles, are smaller airways branching off from the bronchi and are not where gas exchange primarily occurs.

5. Which type of muscle is characterized by involuntary contractions, is striated, and is primarily found in the heart?

• A. Skeletal muscle
• B. Smooth muscle
• C. Cardiac muscle
• D. Elastic muscle

Correct answer: C

Rationale: The correct answer is C, Cardiac muscle. Cardiac muscle fits the description provided in the question as it exhibits involuntary contractions, striations, and is predominantly located in the heart. Skeletal muscle, while also striated, is voluntary and not involuntary like cardiac muscle. Smooth muscle lacks striations and is typically found in the walls of internal organs. Elastic muscle is not a recognized type of muscle tissue in human anatomy, making it an incorrect choice.

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